I have an 8 years old Bryant model 310AAV/JAV and is not heating. I hear it running but the burners are not activating and I see a RED light blinking.

I have a Bryant Model 310AAV/JAV. Furnace and AC are working properly. However, air flow is only going to upstairs. There is no air going through downstairs ducting. Is there a damper or something that controls airflow to downstairs ducting?